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Updated: Dec 21, 2025
Preparation of a Blood Culture Pellet for Rapid Bacterial Identification and Antibiotic Susceptibility Testing
Published on: October 15, 2014
Different growth kinetics in blood components and genetic analysis of Lactococcus garvieae isolated from platelet
Moe Kozakai1, Chieko Matsumoto1, Mami Matsumoto1
1Central Blood Institute, Blood Service Headquarters, Japanese Red Cross Society, Tokyo, Japan.
Background:
In 2014, we experienced the first isolation of Lactococcus garvieae from a platelet concentrate (PC). Thereafter, L. garvieae contamination of PCs occurred in two more cases in Japan. It is rare that bacterial contamination with uncommon strains like this species occurs frequently within a short period. Therefore, we performed a detailed analysis of the characteristics of these strains.
Study Design And Methods:
Three bacterial strains were identified by biochemical testing and molecular analysis. Genomic diversity was characterized by multilocus sequence typing (MLST). To observe growth kinetics in blood components, PCs were inoculated with the three different strains.
Results:
All three strains were identified as L. garvieae by molecular analysis. Each strain belonged to a different phylogenetic group according to MLST analysis. In the spiking trial, the three strains demonstrated differences in their final concentrations and changes in appearance of PCs.
Conclusion:
In this study, all three L. garvieae strains were correctly identified by molecular analysis. Since the three strains were collected in different regions of Japan and belonged to different phylogenetic groups according to MLST analysis, it is suggested that L. garvieae have a wide distribution with diversity in Japan. In PCs, the three L. garvieae strains showed clear differences in growth kinetics and changes in appearance of PCs. These differences may have been the primary determinant of whether PC contamination was detected before transfusion. Moreover, L. garvieae represents an emerging foodborne bacterium that can cause transfusion-transmitted bacteremia. Understanding our cases may help prevent bacterial contamination of blood products.
Insights
Lactococcus garvieae, an emerging foodborne bacterium, can contaminate platelet concentrates (PCs). This study analyzed three diverse strains, revealing differences in growth and appearance that may impact detection and prevent transfusion-transmitted bacteremia.
Area of Science:
- Microbiology
- Transfusion Medicine
- Food Safety
Background:
- First isolation of Lactococcus garvieae from platelet concentrate (PC) in 2014.
- Three subsequent cases of L. garvieae contamination in Japanese PCs occurred within a short period.
- The frequent contamination by this uncommon species prompted a detailed strain analysis.
Purpose of the Study:
- To characterize the genomic diversity of Lactococcus garvieae strains isolated from platelet concentrates.
- To investigate the growth kinetics and impact on platelet concentrate appearance of these strains.
- To understand the implications of L. garvieae contamination for blood product safety and transfusion-transmitted bacteremia.
Main Methods:
- Identification of bacterial strains using biochemical testing and molecular analysis.
- Genomic diversity assessment via multilocus sequence typing (MLST).
- Inoculation of platelet concentrates with different L. garvieae strains to observe growth kinetics and changes in appearance.
Main Results:
- All three strains were confirmed as L. garvieae via molecular analysis.
- MLST revealed each strain belonged to a distinct phylogenetic group, suggesting wide distribution and diversity in Japan.
- Spiking trials showed significant differences in final bacterial concentrations and visual changes in platelet concentrates among the strains.
Conclusions:
- Molecular analysis reliably identified L. garvieae strains.
- The phylogenetic diversity of strains suggests widespread occurrence in Japan.
- Observed differences in growth kinetics and PC appearance highlight potential factors influencing contamination detection and the risk of transfusion-transmitted bacteremia.
